LeetCodeOJ——6. ZigZag Conversion

ZigZag Conversion

The string “PAYPALISHIRING” is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

P A H N
A P L S I I G
Y I R
And then read line by line: “PAHNAPLSIIGYIR”
Write the code that will take a string and make this conversion given a number of rows:

string convert(string text, int nRows);
convert(“PAYPALISHIRING”, 3) should return “PAHNAPLSIIGYIR”.

解题思路：找规律的题，不多说。但说实话题目并没有写清楚，如果是5行，排列顺序是这样的
0 8
1 7 9 15
2 6 10 14
3 5 11 13
4 12
用这样的小例来计算出规律。
代码如下：

class Solution {
public:
    string convert(string s, int numRows) {
        vector<char> ve;
        int len=s.length();
        if (numRows==1){  //别忘了numRows==1时的特殊情况 
            return s;
        }
        for (int i = 0; i < numRows; i++){
             if(i==0){
                 for(int j=i;j<len;j+=2*numRows-2-i){
                     ve.push_back(s[j]);
                 }
             }else if(i==numRows-1){
                 for(int j=i;j<len;j+=numRows-1+i){
                     ve.push_back(s[j]);
                 }
             }else{
                 int k=1,j=i;
                 while(j<len){
                     ve.push_back(s[j]);
                     if(k%2==1){
                         j+=2*numRows-2*i-2;
                     }else{
                         j+=2*i;
                     }
                     k++;
                 }
             }
        }
        string res = "";
        for (int i = 0; i < ve.size(); i++){
            res += ve[i];
        }
        return res;
    }
};